From d70e348e4e9e942ff2766f6d3ba73304de138423 Mon Sep 17 00:00:00 2001
From: Mehdi Drissi <mdrissi@snapchat.com>
Date: Sun, 16 Apr 2023 04:58:00 -0700
Subject: [PATCH 1/2] Support nested namedtuple classes.

---
 mypy/semanal_namedtuple.py                 |  4 ++++
 mypy/semanal_shared.py                     |  4 ++++
 test-data/unit/check-class-namedtuple.test | 18 ++++++++++++++++++
 3 files changed, 26 insertions(+)

diff --git a/mypy/semanal_namedtuple.py b/mypy/semanal_namedtuple.py
index a9f12ceae5c2c..b197eda0d3650 100644
--- a/mypy/semanal_namedtuple.py
+++ b/mypy/semanal_namedtuple.py
@@ -166,6 +166,10 @@ def check_namedtuple_classdef(
                 # And docstrings.
                 if isinstance(stmt, ExpressionStmt) and isinstance(stmt.expr, StrExpr):
                     continue
+                # Allow nested classes.
+                if isinstance(stmt, ClassDef):
+                    self.api.analyze_class(stmt)
+                    continue
                 statements.pop()
                 defn.removed_statements.append(stmt)
                 self.fail(NAMEDTUP_CLASS_ERROR, stmt)
diff --git a/mypy/semanal_shared.py b/mypy/semanal_shared.py
index c86ed828b2b9f..eb6d3418155d0 100644
--- a/mypy/semanal_shared.py
+++ b/mypy/semanal_shared.py
@@ -251,6 +251,10 @@ def process_placeholder(
     ) -> None:
         raise NotImplementedError
 
+    @abstractmethod
+    def analyze_class(self, defn: ClassDef) -> None:
+        raise NotImplementedError
+
 
 def set_callable_name(sig: Type, fdef: FuncDef) -> ProperType:
     sig = get_proper_type(sig)
diff --git a/test-data/unit/check-class-namedtuple.test b/test-data/unit/check-class-namedtuple.test
index 8ae7f6555f9db..6b1b7e7538b96 100644
--- a/test-data/unit/check-class-namedtuple.test
+++ b/test-data/unit/check-class-namedtuple.test
@@ -728,3 +728,21 @@ reveal_type(y) # N: Revealed type is "builtins.int"
 point.y = 6 # E: Property "y" defined in "Point" is read-only
 
 [builtins fixtures/tuple.pyi]
+
+[case testNestedNamedTuple]
+from enum import Enum
+from typing import NamedTuple
+
+class T(NamedTuple):
+  class State(Enum):
+    A =1
+  state:State
+
+class RaggedFeature(NamedTuple):
+  class RowSplits(NamedTuple):
+    x: int
+
+  splits: RowSplits
+
+reveal_type(T.State.A) # N: Revealed type is "Literal[__main__.T.State.A]"
+reveal_type(RaggedFeature.RowSplits.x) # N: Revealed type is "builtins.int"

From 18c6de79ea95dcce23ddbaa494029bcda60ae9ef Mon Sep 17 00:00:00 2001
From: Mehdi Drissi <mdrissi@snapchat.com>
Date: Sun, 16 Apr 2023 21:40:04 -0700
Subject: [PATCH 2/2] fix non-incremental test case

---
 test-data/unit/check-class-namedtuple.test | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/test-data/unit/check-class-namedtuple.test b/test-data/unit/check-class-namedtuple.test
index 6b1b7e7538b96..c82f453a6e7fe 100644
--- a/test-data/unit/check-class-namedtuple.test
+++ b/test-data/unit/check-class-namedtuple.test
@@ -735,8 +735,8 @@ from typing import NamedTuple
 
 class T(NamedTuple):
   class State(Enum):
-    A =1
-  state:State
+    A = 1
+  state: State
 
 class RaggedFeature(NamedTuple):
   class RowSplits(NamedTuple):
@@ -744,5 +744,7 @@ class RaggedFeature(NamedTuple):
 
   splits: RowSplits
 
-reveal_type(T.State.A) # N: Revealed type is "Literal[__main__.T.State.A]"
+reveal_type(T.State.A) # N: Revealed type is "Literal[__main__.State.A]?"
 reveal_type(RaggedFeature.RowSplits.x) # N: Revealed type is "builtins.int"
+
+[builtins fixtures/tuple.pyi]